ADD: Get student by id method.

Spring-Boot-REST-API/src/main/java/com/wasim/rest/api/controller/StudentController.java

@@ -5,14 +5,7 @@
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
-import org.springframework.web.bind.annotation.DeleteMapping;
-import org.springframework.web.bind.annotation.GetMapping;
-import org.springframework.web.bind.annotation.PathVariable;
-import org.springframework.web.bind.annotation.PostMapping;
-import org.springframework.web.bind.annotation.PutMapping;
-import org.springframework.web.bind.annotation.RequestBody;
-import org.springframework.web.bind.annotation.RequestMapping;
-import org.springframework.web.bind.annotation.RestController;
+import org.springframework.web.bind.annotation.*;
 
 import com.wasim.rest.api.entity.Student;
 import com.wasim.rest.api.service.StudentService;
@@ -30,19 +23,24 @@ public ResponseEntity<Student> createStudent(@RequestBody Student student) {
 		return new ResponseEntity<Student>(studentService.createStudent(student), HttpStatus.CREATED);
 	}
 
-	@GetMapping("/getAllStudent")
+	@GetMapping("/getAllStudents")
 	public ResponseEntity<List<Student>> getAllStudent(){
 
 		return new ResponseEntity<List<Student>>(studentService.getAllStudent(), HttpStatus.OK);
 	}
+
+	@GetMapping("/getStudent/{id}")
+	public ResponseEntity<Student> getStudentById(@PathVariable long id){
+		return new ResponseEntity<Student>(studentService.getStudentById(id), HttpStatus.OK);
+	}
 
 	@PutMapping("/editStudent/{id}")
-	public ResponseEntity<Student> updateStudent(@PathVariable("id") long id, @RequestBody Student student){
+	public ResponseEntity<Student> updateStudent(@PathVariable long id, @RequestBody Student student){
 		return new ResponseEntity<Student>(studentService.updateStudent(id, student), HttpStatus.OK);
 	}
 
 	@DeleteMapping("/deleteStudent/{id}")
-	public ResponseEntity<HttpStatus> deleteStudent(@PathVariable("id") long id){
+	public ResponseEntity<HttpStatus> deleteStudent(@PathVariable long id){
 		studentService.deleteStudent(id);
 		return new ResponseEntity<HttpStatus>(HttpStatus.OK);
 	}

Spring-Boot-REST-API/src/main/java/com/wasim/rest/api/entity/Student.java

@@ -17,12 +17,4 @@ public class Student {
 	private String name;
 	private String email;
 	private String address;
-
-
-
-
-
-
-
-
 }

Spring-Boot-REST-API/src/main/java/com/wasim/rest/api/exception/GlobalExceptionHandler.java

@@ -0,0 +1,17 @@
+package com.wasim.rest.api.exception;
+
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ProblemDetail;
+import org.springframework.web.bind.annotation.ControllerAdvice;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+
+@ControllerAdvice
+public class GlobalExceptionHandler {
+    @ExceptionHandler(StudentNotFoundException.class)
+    public ProblemDetail handleStudentNotFoundException(StudentNotFoundException e){
+        ProblemDetail problem = ProblemDetail.forStatus(HttpStatus.NOT_FOUND);
+        problem.setTitle("Student not found.");
+        problem.setProperty("Student id: ", e.getStudentId());
+        return problem;
+    }
+}

Spring-Boot-REST-API/src/main/java/com/wasim/rest/api/exception/StudentNotFoundException.java

@@ -0,0 +1,12 @@
+package com.wasim.rest.api.exception;
+
+public class StudentNotFoundException extends RuntimeException{
+    private final Long studentId;
+    public StudentNotFoundException(Long studentId){
+        super("Student with ID " + studentId + " was not found.");
+        this.studentId = studentId;
+    }
+    public Long getStudentId() {
+        return studentId;
+    }
+}

Spring-Boot-REST-API/src/main/java/com/wasim/rest/api/repository/StudentRepository.java

@@ -6,4 +6,6 @@
 
 public interface StudentRepository extends JpaRepository<Student, Long>{
 
+    Student getStudentById(long id);
+
 }

Spring-Boot-REST-API/src/main/java/com/wasim/rest/api/service/StudentService.java

@@ -7,9 +7,11 @@
 public interface StudentService {
 
 	public Student createStudent(Student student);
-	
+
 	public List<Student> getAllStudent();
-
+
+	public Student getStudentById(long id);
+
 	public Student updateStudent(long id, Student student);
 
 	public void deleteStudent(long id);

Spring-Boot-REST-API/src/main/java/com/wasim/rest/api/service/StudentServiceImpl.java

@@ -2,6 +2,7 @@
 
 import java.util.List;
 
+import com.wasim.rest.api.exception.StudentNotFoundException;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Service;
 
@@ -25,6 +26,14 @@ public List<Student> getAllStudent() {
 		return studentRepository.findAll();
 	}
 
+	@Override
+	public Student getStudentById(long id){
+		if(!studentRepository.existsById(id)){
+			throw new StudentNotFoundException(id);
+		}
+		return studentRepository.getStudentById(id);
+	}
+
 	@Override
 	public Student updateStudent(long id, Student student) {
 		student.setId(id);